1. Field of the Invention
The present invention relates to a terminal for a solenoid which is used, for example, on solenoid-operated valves or sensors
2. Description of the Prior Art
In a conventional solenoid valve (electromagnetic valve) as shown in FIGS. 3 and 4, a solenoid 101 of solenoid valve 20 is covered with a resin molding 201. Solenoid valve 200 has a connector 202 for supplying power to the solenoid 101. Lead wires of solenoid 101 are connected to connector pins.
Solenoid 101 is formed by winding a wire on a resin bobbin 102, as illustrated in FIG. 4. The two end portions of solenoid 101 form lead wires 103, 104. Lead wires 103, 104 are connected by welding (fusing) to weld portions 107, 108 of terminals, that is, base portions of connector pins 105, 106.
When lead wires 103, 104 are welded to weld portions 107, 108, crystals in portions of lead wires 103, 104 adjacent to weld portions 107, 108 become large and rough. Such roughly grown crystals adversely affect the mechanical strength of lead wires 103, 104.
Solenoid valves are used in, for example, various control mechanisms in automotive engines. As an engine is repeated operated and stopped, the hot-cold cycles repeated expand and shrink resin mold 201 of solenoid valve 200, moving solenoid 101 back and forth. Because of such expansion and shrinkage, the portions adjacent to weld portions 107, 108 at which lead wires 103, 104 of solenoid 101 are fixed, receive tensile loads. Although the portions of lead wires 103, 104 adjacent to weld portions 107, 108 have roughly grown crystals that adversely affect the mechanical strength thereof as described above, conventional solenoid valves are designed so that no significant problems occur under normal working conditions.
However, there is a growing demand for increased service life of various component parts of motor vehicles or other machines that include solenoid valves and various sensors.